Spring Actuated Rocking Mechanism for Collapsible Chair

ABSTRACT

A spring actuated rocking mechanism can be attached to the legs of a collapsible chair to allow for the user to rock in the collapsible chair. The mechanism may be attached at the factory or retrofitted to the chair. The rocking mechanism can be attached to the end of a leg or disposed within a leg, having a leg portion above and below the mechanism.

REFERENCE TO RELATED CASE

This application claims priority under 35 U.S.C. §119 (e) to provisional application No. 61/948,780 filed on Mar. 6, 2014, the content of which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a spring actuated mechanism as part of a collapsible chair, which enables the user to enjoy a rocking chair type motion during leisure or outdoor activities. Prior practices typically consisted of curved rocking members joined to the front and rear chair legs. These members must be folded as a secondary action by the user upon deploying the chair for use, or compacting the chair for storage. This takes extra time and effort in setting up or putting the chair away.

The invention is intended to be incorporated as an integral part of a collapsible chair frame where a portion of the rear legs of the chair may be replaced by the device. This configuration allows the chair to be folded to its closed configuration without the user disconnecting any other embodiments. This type of rocker also achieves the rocking motion by means of a compressive spring attached to the rear frame members of the chair rather than traditional curved rocking members joined to the front and rear legs of the chair frame.

SUMMARY OF THE INVENTION

The present invention is directed to a rocking mechanism to attach to a single leg of a collapsible chair that includes an upper portion, the upper portion having a first opening in a top end, the first opening configured to receive at least a portion of the single leg of the collapsible chair, a spring, the spring disposed against the upper portion such that a proximal portion of the spring engages a portion of the upper portion; and a lower portion, the lower portion configured to engage a distal end of the spring, wherein the spring compresses when pressure is exerted on the upper portion.

In yet another aspect, the rocking mechanism includes a guide member, the guide member fixedly attached to the lower portion and movable within at least a portion of the upper portion.

In some embodiments, the upper portion has a top end and bottom end, the lower portion has an upper end and the upper end of the lower portion is disposed between the top end and the bottom end of the upper portion.

In other embodiments, one of the upper portion and the lower portion has a cavity therein and the other of one of the upper portion and the lower portion is disposed within the cavity thereby sealing the spring within the rocking mechanism.

In other embodiments, the upper and the lower portions engage a portion of the leg of the chair.

Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description and the following detailed description of the present embodiments of the invention, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention, and together with the description serve to explain the principles and operations of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of one embodiment of a rocking mechanism according to the present invention;

FIG. 2 is a perspective, exploded view of the rocking mechanism of FIG. 1;

FIG. 3 is a cross section of the rocking mechanism of FIG. 1;

FIG. 4 is a plan view of another embodiment of a rocking mechanism according to the present invention;

FIG. 5 is a perspective, exploded view of the rocking mechanism of FIG. 4;

FIG. 6 is a cross section of the rocking mechanism of FIG. 4;

FIG. 7 is a plan view of another embodiment of a rocking mechanism according to the present invention;

FIG. 8 is a perspective, exploded view of the rocking mechanism of FIG. 7;

FIG. 9 is a cross section of the rocking mechanism of FIG. 7;

FIG. 10 is an enlarged perspective cross-sectional view of a portion of the top and bottom portions of the rocking mechanism of FIG. 1 showing the alignment member and alignment groove:

FIG. 11 is a plan view of another embodiment of a rocking mechanism according to the present invention;

FIG. 12 is a perspective, exploded view of the rocking mechanism of FIG. 11;

FIG. 13 is a cross section of the rocking mechanism of FIG. 11;

FIG. 14 is a plan view of another embodiment of a rocking mechanism according to the present invention;

FIG. 15 is a perspective, exploded view of the rocking mechanism of FIG. 14; and

FIG. 16 is a cross section of the rocking mechanism of FIG. 14.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present preferred embodiment(s) of the invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

Referring to FIGS. 1-3, a first embodiment of a rocking mechanism 20 is illustrated. The rocking mechanism 20 is preferably attached to a rear leg of a collapsible chair (not shown). Therefore, in order to make a collapsible chair (such as that produced by the current assignee of this patent application and illustrated in U.S. Pat. No. D593,759, the contents of which are hereby incorporated by reference herein), two of the rocking mechanisms 20 can be attached to the rear legs. As one of ordinary skill in the art would recognize, the cross members of the illustrated chair may need to be adjusted to accommodate the rocking mechanisms 20. Clearly, the rocking mechanisms 20 could also be added to other such collapsible chairs. It should also be noted that the rocking mechanisms 20 can be added upon manufacture of the chair or added thereafter. As illustrated in the figures, a portion of a chair leg 22 is illustrated.

The rocking mechanism 20 has an upper portion 24, the upper portion 24 having a first opening 26 in a top end 28, the first opening 26 configured to receive at least a portion of the chair leg 22 of the collapsible chair. The upper portion 24 also has a second opening 30 on a side portion 32, the second opening 30 being configured to receive a securing member 34 to engage and maintain the chair leg 22 in the upper portion 24. As such, the second opening 30 is in communication with the first opening 26. The upper portion 24 may also have a corresponding second second opening 36 to receive another securing member 38. The second second opening 36 is therefore also in communication with the first opening 26. See FIG. 3.

The upper portion 24 may have any number of external configurations and fall within the scope of the present invention. As illustrated, the upper portion 24 includes a generally cylindrical portion 40 adjacent the top end 28, and then a frustoconical portion 42 immediately adjacent the cylindrical portion 40. The frustoconical portion 42 becomes larger in diameter the farther away from the cylindrical portion 40. The upper portion 24 then includes a shoulder 44 that faces away from the top end 28 and the frustoconical portion 42. In fact, the shoulder 44 is formed by the frustoconical portion 42 and a second frustoconical portion 46 that extends distally from the shoulder 44. The second frustoconical portion 46 then decreases in diameter the farther away from the first frustoconical portion 42.

The rocking mechanism also includes a spring 50, the spring 50 having a first end 52 that is disposed against the shoulder 44 of the upper portion 24. The first end 52 of the spring 50 engages the shoulder 44 and surrounds at least a portion of the second frustoconical portion 46. The spring 50 is preferably a coil spring, but other configurations are possible as well. The spring 50 has a second end 54 that engages a lower portion 70. The lower portion 70 is configured to engage the second end (distal end) 54 of the spring 50. Specifically, the lower portion 70 has a shoulder 72 facing upwards and toward the upper portion 24. The lower portion 70 preferably has a rounded surface 74 on an opposite side of the lower portion 70 from the shoulder 72. The lower portion 70 also includes a projection 76 radially inward from the shoulder 72 to assist in centering the spring 50 on the lower portion 70 and the shoulder 72. The lower portion 70 may also have a center opening 78 that holds a guide member, as discussed in detail below.

The rocking mechanism 20 also includes a guide member 90 that extends between the upper portion 24 and the lower portion 70. The guide member 90 has a first end 92 and a second end 94. The first end 92 of guide member 90 includes a circular groove 96 extending around the periphery of guide member 90. The groove 96 is configured to receive therein a circular retaining clip 98. The second end 94 guide member 90 has a longitudinal opening 100 therein to receive a fastening member 102. The fastening member 102 extends through the center opening 78 of the lower portion 70 to engage the guide member 90 and maintain it in a fixed relation thereto. The fastening member 102 is preferably a threaded screw to engage corresponding threads inside the longitudinal opening 100 of the guide member 90. A cap 104 is also provided to be press-fit into the center opening 78 from the rounded surface 74.

The first end 92 of the guide member 90 is movable within the first opening 26, which as best illustrated in FIG. 3 extends throughout the length of the upper portion 24. Extending into the first opening 26 toward the distal end thereof and adjacent to the second frustoconical portion 46 is an inward extending ring 106. The guide member 90, having the retaining clip 98 inserted into the groove 96, is inserted into the first opening 26. The retaining clip 98 in gauges the inward extending ring 106 to prevent the guide member 90 from falling out the bottom end 110 of the upper portion 24. The spring 50 is then disposed over and around the guide member 90 and the second frustoconical portion 46 to engage the shoulder 44. The lower portion 70 is then attached to the guide member 90 as discussed above. The second end 54 of spring 50 engages the upward facing shoulder 72 of the lower portion 70.

A bushing 112 is preferably disposed in the bottom end 110 of the upper portion 24. As best seen in FIG. 3, the bushing 112 aligns and provides a wearable surface during linear movement of the guide member 90 in and out of the first opening 26 during use. As can be imagined, applying force to the rocking mechanism 20 through the chair leg 22 causes compression of the spring 50, lowering of the upper portion 24 relative to the lower portion 70 thereby causing the guide member 92 move upward in the first opening 26. Thus, the bushing 112 helps to keep the upper portion 24, the spring 50, and the lower portion 70, in alignment during use.

The upper portion 24 and the lower portion 70 are preferably made from a high density polyethylene. The bushing 112 is preferably made of acetyl resin, while the guide member 90 is preferably made from stainless steel. The other parts of the rocking mechanism 20 are all preferably made from steel. It should be noted however that other appropriate materials may be used in the manufacture of the rocking mechanism 20 and still fall within the scope of the present invention.

It should be noted that the first opening 26 has a larger diameter adjacent the top end 28 of the upper portion 24. The change in diameter of the first opening 26 below the second openings 30, 36 provides for a shoulder 120 that supports the end of chair leg 22.

A second embodiment of a rocking mechanism 200 is illustrated in FIGS. 4-6. While many of the components in rocking mechanism 200 are similar to rocking mechanism 20, the chair leg 22 has been omitted. It is understood, however, that a chair leg such as leg 22 would be fixed to the rocking mechanism 200 in the same manner as described above.

The rocking mechanism 200 has an upper portion 224, the upper portion 224 having a first opening 226 in a top end 228 configured to receive at least a portion of a chair leg of a collapsible chair. The upper portion 224 also has a second opening 230 on a side portion 232, the second opening 230 being configured to receive a securing member (not shown, but may be the same as or similar to the one for rocking mechanism 20) to engage and maintain the chair leg in the upper portion 224. As such, the second opening 230 is in communication with the first opening 226. The upper portion 224 may also have a corresponding second second opening 236 to receive another securing member. The second second opening 236 is therefore also in communication with the first opening 226. See FIG. 6.

The upper portion 224 may, like the other embodiment, have any number of external configurations and still fall within the scope of the present invention. As illustrated, the upper portion 224 includes a generally cylindrical portion 240 adjacent the top end 228, and then a frustoconical portion 242 immediately adjacent the cylindrical portion 240. The frustoconical portion 242 becomes larger in diameter the farther away from the cylindrical portion 240. The upper portion 224 then includes a shoulder 244 that faces away from the top end 228 and the frustoconical portion 242. In fact, the shoulder 244 is formed by the frustoconical portion 242 and a second frustoconical portion 246 that extends distally from the shoulder 244. The second frustoconical portion 246, which is substantially shorter than the first frustoconical portion 242, then decreases in diameter the farther away from the first frustoconical portion 242.

The rocking mechanism 200 also includes a spring 250, the spring 250 having a first end 252 that is disposed against the shoulder 240 of the upper portion 224. The first end 252 of the spring 250 engages the shoulder 244 and surrounds at least a portion of the second frustoconical portion 246. The spring 250 is preferably a coil spring, but other configurations are possible as well. The spring 250 has a second end 254 that engages a lower portion 270. The lower portion 270 is configured to engage the second end (distal end) 254 of the spring 250. The lower portion 270 has a shoulder 272 facing upwards and toward the upper portion 224. The lower portion 270 is thicker than the lower portion 70 of the first embodiment, but also preferably has a rounded surface 274 on an opposite side of the lower portion 270 from the shoulder 272. The lower portion 272 also includes a projection 276 disposed radially inward from the shoulder 272 to assist in centering the spring 250 on the lower portion 270. The lower portion may also have a center opening 278 that holds a guide member, as discussed in detail below.

The rocking mechanism 200 also includes a guide member 290 that extends between the upper portion 224 and the lower portion 270. The guide member 290 has a first end 292 and a second end 294. The second end 294 of guide member 290 has a longitudinal opening 300 therein to receive a fastening member 302. The fastening member 302 extends through the center opening 278 of the lower portion 270 to engage the guide member 290 and maintain it in a fixed relation thereto. The fastening member 302 is preferably a threaded screw to engage corresponding threads inside the longitudinal opening 300 of the guide member 290.

The first end 292 of the guide member 290 is movable with in the first opening 226, which as best illustrated in FIG. 6, extends throughout the length of the upper portion 224. A bushing 312 is preferably disposed in the bottom end 310 of the upper portion 224. As illustrated in FIG. 6, the bushing 312, which is preferably made from a self-lubricating metal such as brass, aligns and provides a wearable surface during linear movement of the guide member 290 in and out of the first opening 226 during use. The bushing 312 is preferably injection-molded into the upper portion 224. As can be imagined, applying force to the rocking mechanism 200 through the chair leg causes compression of the spring 250, lowering the upper portion 224 relative to the lower portion 270 thereby causing the guide member 292 to move upward in the first opening 226. Thus, the bushing 312 helps to keep the upper portion 224, the spring 250, and the lower portion 270 in alignment during use.

The guide member 290 is combined with a retaining member 298 inserted into the first end 292 of the guide member 290. The retaining member 298 is preferably a screw that engages with threads in a longitudinal opening at the first end 292 of the guide member 290. The retaining member 298 which has a larger head diameter than that of the guide member 290, engages the bushing 312 to prevent the guide member 290 from falling out the bottom end 310 of the upper portion 224. The spring 250 is then disposed over and around the guide member 290 end the second frustoconical portion 246 to engage the shoulder 244. The lower portion 270 is then attached to the guide member 290 as discussed above. The second end 254 of spring 250 engages the upward facing shoulder 272 of the lower portion 270.

Another embodiment of a rocking mechanism 400 is illustrated in FIGS. 7-10. The rocking mechanism 400 has an upper portion 424, the upper portion 424 having a first opening 426 in a top end 428, the first opening 426 configured to receive at least a portion of the chair leg 22 of the collapsible chair. While not illustrated, the upper portion 424 may also have a second opening configured to receive a securing member to engage and maintain the chair leg 22 in the upper portion 424 as with other embodiments.

The upper portion 424 may, like the other embodiments, have any number of external configurations and still fall within the scope of the present invention. As illustrated, the upper portion 424 includes a generally rounded (or domed) portion 440 adjacent the top end 428, and then a cylindrical portion 442 immediately adjacent the rounded portion 440. The cylindrical portion 442 terminates with a circumferential ring 444 (for reasons discussed below) and a flat bottom end 410 that faces away from the top end 428.

The rocking mechanism 400 also includes a spring 450, the spring 450 having a first end 452 that is disposed against the bottom end 410 of the upper portion 424. The spring 450 is preferably a coil spring, but other configurations for the spring 450 are possible as well. The spring 450 has a second end 454 that engages a lower portion 470. The lower portion 470 is generally cylindrical and is configured to receive the second end (distal end) 454 of the spring 450 and at least a portion of the upper portion 424. In particular, the lower portion 470 has a flat bottom 472 to engage the second end (distal end) 454 of the spring 450. Around the inside of lower portion 470 at a top end 446 thereof is an annular ring 474 to engage the circumferential ring 444 of the upper portion 424 to keep the spring 450 from separating the lower portion 470 from the upper portion 424. The two rings 444, 474 engage one another, preventing the lower portion 470 from exiting the upper portion 424. The two portions 424, 470 can be snap fit together. As a result of this configuration, it should be noted that the top end 478 of the lower portion 470 is always positioned between the top end 428 and the bottom end 410 of the upper portion 424.

The lower portion 470 also has a vertically oriented groove 476 that cooperates with a projection 478 on the upper portion 424. See FIG. 9. FIG. 10, a perspective view of the rocking mechanism 400 in cross section, shows the projection 478 on the upper portion 424 engaging the vertically oriented groove 476. The combination of the groove 476 and the projection 478 prevents the lower portion 470 and the upper portion 424 of the rocking mechanism 400 from rotating relative to one another. This is important as rocking mechanism 400 has a foot portion 480 into which the lower portion 470 is placed. The foot portion 480 has a curved bottom portion 482 to assist with the rocking motion. The curved bottom portion 482 has two generally flat surfaces 482 a, 482 b that lie in two different planes that form an angle ∝, which is about 28°. The surface 482 b forms an angle β with a center line of the rocking mechanism—see FIG. 7. Preferably, this angle is about 76°. Since the curved bottom portion 482 has surfaces that are direction oriented, unlike the embodiments disclosed above, the foot portion 480 needs to be maintained in the correct orientation. The combination of the groove 476 and the projection 478 maintain this orientation.

Another embodiment of a rocking mechanism 600 is illustrated in FIGS. 11-13. The rocking mechanism 600 has an upper portion 624, the upper portion 624 having a first opening 626 in a top end 628, the first opening 626 configured to receive at least a portion of the chair leg 22 of the collapsible chair. While not illustrated, the upper portion 624 may also have a second opening configured to receive a securing member to engage and maintain the chair leg 22 in the upper portion 624 as with the other embodiments.

The upper portion 624 may, like the other embodiments, have any number of external configurations and still fall within the scope of the present invention. As illustrated, the upper portion 624 includes a generally rounded (or domed) portion 640 adjacent the top end 628, and then a cylindrical portion 642 immediately adjacent the rounded portion 640. The cylindrical portion 642 is generally hollow and extends downward sufficiently far enough so as to contain the spring 650. The cylindrical portion 642 has a projection 660 that extends downward from the domed portion 640 to engage the spring 650 and maintain it centrally in the rocking mechanism 600. The upper portion 624 has an inner surface 662 that has a circumferential ring 644 extending into the cylindrical portion 642 to engage the lower portion 670 as discussed below.

The rocking mechanism 600 also includes a spring 650, the spring 650 having a first end 652 that is disposed against projection 660 of the upper portion 624. The spring 650 is preferably a coil spring, but other configurations of the spring 650 are possible as well. The spring 650 has a second end 654 that engages the lower portion 670. The lower portion 670 is generally cylindrical and has a flat top surface 672 to engage the second end (distal end) 654 of the spring 650. Around the outside of lower portion 670 is an annular ring 674 to engage the circumferential ring 644 of the upper portion 624 to keep the spring 650 from separating the lower portion 670 from the upper portion 624. The two rings 644, 674 engage one another, preventing the lower portion 670 from exiting the upper portion 624. The two portions 624, 660 can be snap fit together. The bottom of the lower portion 670 is rounded as with the first two embodiments to assist in the rocking motion of the chair.

Rocking mechanism 800 is illustrated in FIGS. 14-16. Rocking mechanism 800 is configured to be inserted into the leg of a collapsible chair, rather than be on the end portion of a leg as with the prior embodiments. As such, rocking mechanism 800 has leg portions 22 connected to both ends thereof, with a foot 24 attached to the bottom leg 22. Rocking mechanism 800 has an upper portion 802 that includes a cap 804 and a cylinder 806. The cap 804 and the cylinder 806 are illustrated as two pieces but they could be made as one integral unit. The cap 804 and the cylinder 806 can be secured to one another by a press-fit, since the cap 804 has a lip 808 that engages the cylinder 806 to prevent the cap 804 from being inserted too far. Additionally, the cap 804 and the cylinder 806 can be attached to one another by any other method, such as with an adhesive, welded, ultrasonically welded, with screws or rivets, etc. The cap 804 has an opening 810 on the top side 812 thereof that is configured to receive the upper portion of the chair leg 22. The top side 812 includes a cylindrical portion 814 that could have an opening therein to accept a securing member to secure the leg 22 in the opening 810. Alternatively, the chair leg 22 can be secured into the opening 810 by a press-fit, adhesives, welding, etc. The underside of the cap 804 has a centrally located projection 816 that extends into the cylinder 806. The projection 816 centers a spring 850 within an interior space 818 in the cylinder 806.

The rocking mechanism 800 also has a lower portion 870 that is at least partially disposed within the interior space 818 of the cylinder 806 of the upper portion 802. The lower portion 870 has a cup-shaped main portion 872 and a projection 874 extending from the bottom side 876 thereof. The projection 874 is configured to engage the lower leg 22. As illustrated in FIG. 16, the projection 874 is inserted into the lumen of the leg 22. However, the lower portion 870 may also be configured such that the leg 22 is inserted into an opening in the lower portion 870. The main portion 872 is configured to receive an end 854 of the spring therein. The lower portion 870 is movable relative the upper portion 802 and in particular, the lower portion 870 slides up and down in the interior space 818 of the cylinder 806.

To maintain the lower portion 870 in the upper portion 802, a sealing member 830 is used. The sealing member 830, similar to the cap 804, is partially inserted into the interior space 818 of the cylinder 806. The projection 874 protrudes through an opening 832 in the sealing member 830. The opening 832 may also be large enough to allow the leg 22 to be inserted therein as well. The sealing member 830 may be secured to the cylinder 806 in any appropriate manner, as discussed above.

While it is noted that the upper leg 22 is inserted into the opening 810, the rocking mechanism 800 can be inverted relative to the chair so that the lower leg 22 is inserted into the opening 810.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. 

I claim:
 1. A rocking mechanism to attach to a single leg of a collapsible chair comprising: an upper portion, the upper portion having a first opening in a top end, the first opening configured to receive at least a portion of the single leg of the collapsible chair; a spring, the spring disposed against the upper portion such that a proximal portion of the spring engages a portion of the upper portion; and a lower portion, the lower portion configured to engage a distal end of the spring, wherein the spring compresses when pressure is exerted on the upper portion.
 2. The rocking mechanism according to claim 1, further comprising a guide member, the guide member fixedly attached to the lower portion and movable within at least a portion of the upper portion.
 3. The rocking mechanism according to claim 1, wherein the lower portion functions as a foot to engage a surface.
 4. The rocking mechanism according to claim 1, further comprising a foot portion disposed around at least a portion of the lower portion to engage a surface.
 5. The rocking mechanism according to claim 1, wherein the upper portion has a top end and bottom end, the lower portion has an upper end and the upper end of the lower portion is disposed between the top end and the bottom end of the upper portion.
 6. The rocking mechanism according to claim 5, wherein one of the upper portion and the lower portion has a cavity therein and the other of one of the upper portion and the lower portion is disposed within the cavity thereby sealing the spring within the rocking mechanism.
 7. The rocking mechanism according to claim 1, wherein the upper portion has at least one second opening therein, the at least one second opening in communication with the first opening to allow a securing member to be inserted into the at least one second opening to secure the single leg of a collapsible chair to the upper portion.
 8. The rocking mechanism according to claim 7, wherein the at least one second opening comprises two second openings, the two second openings lying on the same axis and wherein the securing member comprises a first securing member and a second securing member, the first and second securing members capable of engaging one another.
 9. The rocking mechanism according to claim 2, wherein the spring is coaxial with the guide member.
 10. The rocking mechanism according to claim 2, wherein the spring is under constant compression between the upper and lower portions.
 11. The rocking mechanism according to claim 2, wherein the first opening in the top end of the upper portion extends through the upper portion, the guide member being disposed within the first opening through a bottom end of the upper portion. 